1. Field of the Invention
The present invention generally relates to a wheel assembly and more particularly to an improved bearing for wheeled luggage.
2. Description of Related Art
Conventionally, two metal bearings are provided in a wheel of luggage. But this is unsatisfactory because (1) it is relatively high in cost; and (2) it may produce loud sounds when operated. Typically, a metal bearing is not a high quality product required by luggage manufacturer because metal bearings for wheeled luggage do not operate so frequently as a machine bearing. Further, such metal bearings tend to become rusted after a long time of non-use. As such, wheeled luggage does not operate smoothly in most cases. Even worse, the loud sounds produced by a luggage rolling across a supporting surface in an airport often makes the traveler embarrassed.
A number of designs have been developed to eliminate the above deficiencies. For example, U.S. Pat. No. 5,134,753, entitled "Luggage Caster" and U.S. Pat. No. 5,295,565, entitled "Wheeled Luggage" both do not employ a metal bearing in the wheel assembly but rather wheel directly. Such designs are disadvantageous because a strong frictional resistance exists between the metal axle and the plastic wheel when luggage rolls across a supporting surface. worse, a considerable heat is generated between the metal axle and wheel when the luggage is loaded and transported a long distance which in turn tends to cause the bore to deform, thereby deactivating the wheel assembly.
An improved design that aims at solving the above problem is to mount two washers W on axle in either side of the wheel, i.e., between and attached to the wheel and the inner surface of the wheel mount as shown in FIG. 11. As such, neither side of the wheel is not in contact with the inner surface of wheel mount. Such washers W aim at decreasing the frictional resistance between the wheel assembly and the wheel mount. However, the above high heat disadvantage still exists when operated. As a result, the problem of deformed plastic wheel is unsolved.
Thus, it is desirable to provide an improved bearing for wheeled luggage in order to overcome the above drawbacks of prior art.